CBSE Physics Sample Question Paper : Set-5
Q. 1. The refractive index of the material of an equi-double convex lens is 1.5. Write the relation between the focal length and the radius of curvature?
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Q. 2. What is the wavelength range of microwaves?
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Q. 3. Indicate the position of a magnetic diopole held in a magnetic field, where its potential energy is minimum.
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Q. 4. Write the value of the critical angle for a material of refractive index V2.
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Q.5. If the frequency of tight falling on a metal surface is doubled, will the kinetic energy of emitted photoelectrons doubled?
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Q. 6. How is a Gauss related to Weber/ (metre) 2?
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Q. 7. Why sky waves are not used in the transmission of television signals?
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Q. 8. What factors make a fusion reactions difficult to achieve?
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Q. 9. A a.c. voltage E = Eo sin cor is applied across an inductance L. Obtain an expression for the current/.
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Q. 10. Draw a labelled energy level diagram for the decay of 6027 Co mucleus.
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Q. 11. A charged particle is moving on a circular path of radius R in a uniform magnetic field under the Lorentz’s force F. How much work is done by the force in one round? Is the momentum of the particle changing?
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Q. 12. What is the effect of increasing the diameter of the objective of a telescope on its (i) magnifying power and (ii) resolving power?
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Q.13. What are magnetic lines of force? Roughly trace the magnetic field lines for a bar magnet.
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Q. 14. Define Coulomb. Calculate the charge carried by 12.5 X 108 electrons.
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Q. 15. State any two conditions under which light from two sources can interfere.
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Q. 16. (i) Define the term electrolysis.
(ii) Give two factors which are responsible for lower electrical conductivity of electrolytes than metals at room temperature.
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Q. 17. Light of wavelength 5500 A falls on a slit of width 0.13 cm. at normal incidence. Calculate the width of the central maximum on a screen kept 5 m away from the slit.
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Q. 18. State Ohms’ law. On what factors the resistance of a conductor depend?
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Q. 19. Obtain Bohr’s quantization condition of angular momentum on the basis of the wave picture of electron.
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Q. 20. State the magnetic properties of steel and soft iron.
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Q. 21. State tangent law. How will the reduction factor of a tangent galvanometer change when the number of turns of its coil is doubled?
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Q. 22. Prove by reasoning (without performing any calculations) that the magnetic field B on the axis at an end face of a very long solenoid is half the value in the middle of the solenoid.
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Q. 23. Define the atomic mass unit. Express its value in electron volt.
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Q. 24. In Fig. the rectangular loop of wire is being pulled to the right. What is the direction of the induced current in the loop?
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Q. 25. The energy required to ionize a hydrogen atom is 13.6 eV. It is to be ionized by the inelastic collision of (i) an electron, (ii) a hydrogen ion, (iii) a helium ion. Which of these particles must have the higher initial kinetic energy for ionization?
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Q. 26. Show that an electron of mass m entering uniform magnetic field B with a velocity v moves in a circular path.
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Q. 27. Define electric potential in an electrostatic field and express it as the line integral of the electrostatic field intensity.
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Q. 28. (a) Two conductors of capacitance C1 and C2 are charged to potential V1 and V2. They are then connected together. Calculate the common pctential and also the charges on each after connecting.
(b) A capacitor of capacitance 1.77 x 10-10 farad has a p.d. of 3000 V. Whena 0.01 m thick sheet of dielectric material is put between the plates, the p.d. reduces to 10O0 V. Find the (i) Charge on each plate, (ii) Dielectric constant of the sheet, (iii) Capacitance of capacitor after putting the sheet, (iv) permittivity of the dielectric medium.
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Q. 29. Explain the term ‘chain reaction’. What are the functions of moderator and control rods in a nuclear reactor?
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A stream of neutrons have a kinetic energy 0.0327 eV. How many half lives are spent by the neutron in a distance of 10 km ?
(Given half life of neutron equal to 700 seconds; mass of the neutron = 1.675 x 10-27 kg).
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Q. 30. When a metal surface is irradiated with light of wavelength 4950 A, a photocurrent appears which vanishes at a retarding potential of 0.6 volt. When a different source is used, it is found that the retarding potential is now 1.1 volt. Calculate the work function of the metal surface and the wavelength of the second source.
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